PHP krsort() Function

The krsort() function is an inbuilt function in PHP which is used to sort an array by key in reverse order according to its index values. It sorts in a way that relation between indices and values is maintained.

Syntax:

bool krsort( $array, $sorting_type )

Parameters: This function accepts two parameters as mentioned above and described below:

• $array: This parameter specifies the array which to be sort. It is a mandatory parameter.
• $sorting_type: This is an optional parameter. There are different sorting types which are discussed below:
  • SORT_REGULAR: The value of $sorting_type is SORT_REGULAR then items are compare normally.
  • SORT_NUMERIC: The value of $sorting_type is SORT_NUMERIC then items are compares numerically.
  • SORT_STRING: The value of $sorting_type is SORT_STRING then items are compares as string.
  • SORT_LOCALE_STRING: The value of $sorting_type is SORT_STRING then items are compares as string, based on current locale.

Return Value: This function returns True on success or False on failure.

Below programs illustrate the krsort() function in PHP.
Program 1:

<?php
// PHP program to illustrate
// krsort()function

// Input different array elements
$arr = array("0" =>"Technology",
             "1" =>"Machine",
             "2" =>"GeeksforGeeks",
             "3" =>"Graphics",
             "4" =>"Videos",
             "5" =>"Report",
             "6" =>"Article",
             "7" =>"Placement",
             "8" =>"Contribute",
             "9" =>"Reset",
             "10" =>"Copy",
        );

// Implementation of krsort()
krsort($arr);

// for-Loop for displaying result
foreach ($arr as $key => $val) {
    echo "[$key] = $val";
    echo"\n";
}

?>

Output:

[10] = Copy
[9] = Reset
[8] = Contribute
[7] = Placement
[6] = Article
[5] = Report
[4] = Videos
[3] = Graphics
[2] = GeeksforGeeks
[1] = Machine
[0] = Technology

Program 2:

<?php
// PHP program to illustrate
// krsort function

// Input different array elements
$arr = array("a" => 11,
             "b" => 22,
             "d" => 33,
             "n" => 44,
             "o" => 55,
             "p" => 66,
             "r" => 77,
             "s" => 2,
             "q" => -11,
             "t" => 3,
             "u" => 1000,
             "z" => 1,
        );
// Implementation of krsort
krsort($arr);

// for-Loop for displaying result
foreach ($arr as $key => $val) {
    echo "[$key] = $val";
    echo"\n";
}

?>

Output:

[z] = 1
[u] = 1000
[t] = 3
[s] = 2
[r] = 77
[q] = -11
[p] = 66
[o] = 55
[n] = 44
[d] = 33
[b] = 22
[a] = 11

Reference: http://php.net/manual/en/function.krsort.php